1. Field
Example embodiments herein relate to a carbon dioxide absorbent including an amorphous mixed metal oxide, a method of producing the same, a carbon dioxide capture module including the same, and a method of separating carbon dioxide using the same.
2. Description of the Related Art
A considerable increase in the concentration of global atmospheric CO2, one of the greenhouse gases, has raised concern about climate change and has led to increasing efforts in research and development on control of CO2 emissions. The main CO2 emission sources include fossil fuel-based power plants, vehicles, and manufacturing plants for cement, limestone, hydrogen, ammonia, and the like. Capture and separation of carbon dioxide from fixed facilities such as various power plants or factories are considered as first measures for the control of CO2 emissions. The capture of carbon dioxide refers to a process of physically or chemically separating CO2 from a gas mixture exhausted from chemical reactions or combustion of fossil fuels. Among solid powder materials being used for capturing CO2 by adsorption are carbon materials, zeolites, metal-organic framework (MOF)/zeolitic-imidazolate framework (ZIF), hydrotalcite, and metal oxides. The carbon materials, zeolites, and MOF/ZIF show a certain level of adsorption efficiency at a relatively low temperature of from 0° C. to room temperature, and the metal oxides show a certain level of adsorption efficiency at a relatively high temperature of 500° C. or higher. Hydrotalcite is one of adsorbents that can be used at a middle temperature range of 150° C. to 400° C., but its adsorption capacity is only about 1 to 2 wt %. Among fixed CO2-emission facilities emitting a considerable amount of carbon dioxide are fossil fuel-based power plants (e.g., an integrated gasification combined cycle (IGCC) system or a thermoelectric power plant) and natural gas wells. In order to address cost-related issues, power plants emitting a relatively large amount of carbon dioxide require adsorbent materials that may adsorb carbon dioxide at a relatively high temperature, for example, about 200° C. to 550° C.